Exploring doped or vacancy-modified graphene-based electrodes for applications in asymmetric supercapacitors

Autor(es)

da Silva, Debora A. C. ^[1] ; Paulista Neto, Antenor J. ^[2] ; Pascon, Aline M. ^[1] ; Fileti, Eudes E. ^[2] ; Fonseca, Leonardo R. C. ^[3] ; Zanin, Hudson G. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Ctr Innovat New Energies, Adv Energy Storage Div, Carbon Sci Tech Labs, Sch Elect & Comp Engn, Ave Albert Einstein 400, BR-13083852 Campinas, SP - Brazil

^[2] Univ Fed Sao Paulo, Inst Sci & Technol, BR-12247014 Sao Jose Dos Campos, SP - Brazil

^[3] Univ Fed Minas Gerais, Dept Phys, Ave Pres Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 22, n. 7, p. 3906-3913, FEB 21 2020.
• Citações Web of Science: 9

Resumo

We report here density functional theory calculations and molecular dynamics atomistic simulations to determine the total capacitance of graphene-modified supercapacitors. The contributions of quantum capacitance to the total capacitance for boron-, sulfur-, and fluorine-doped graphene electrodes, as well as vacancy-modified electrodes, were examined. All the doped electrodes presented significant variations in quantum capacitance (ranging from 0 to similar to 200 mu F cm(-2)) due to changes in the electronic structure of pristine graphene. The graphene-modified supercapacitors show any appreciable effect on double-layer capacitance being virtually the same for all the devices investigated. The total differential capacitance was found to be limited by the quantum capacitance, and for all the systems, it is lower than the quantum capacitance over the entire voltage window. We found that the total capacitance can be optimized by considering an adequate modification to each electrode in the supercapacitor. In addition, we found that an asymmetric supercapacitor assembled with different doped electrodes, i.e. an F doped negative electrode and an N doped positive electrode, is the best choice for a supercapacitor since this combination results in better capacitance over the entire potential window. (AU)

• Processo FAPESP: 17/11631-2 - CINE: desenvolvimento computacional de materiais utilizando simulações atomísticas, meso-escala, multi-física e inteligência artificial para aplicações energéticas
• Beneficiário: Juarez Lopes Ferreira da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia
• Processo FAPESP: 17/11958-1 - CINE - Divisão para Armazenamento de Energia Avançado
• Beneficiário: Rubens Maciel Filho
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia